Telephone calls remain a desirable manner of communication despite the proliferation of alternative mediums. Because a called party is not always available to answer a call, a variety of methods have been developed to record messages intended for the called party. Answering machines, voice mail systems, and to a lesser extent answering services are all well known to modern telephone users. All of these systems, however, require that the called telephone number be operational.
Telecommunication systems have also been proposed to address situations in which circuits are unavailable to complete a telephone call. For example, U.S. Pat. No. 5,844,974 shows an emergency telephone communications system that allows communications during congestion in the event of disaster. This patent suggests that when exchanges are overloaded due to simultaneous calling by a majority of subscribers during emergency situations, the subscribers may send messages about their safety to important parties.